Wireless base station, wireless communication terminal, and wireless communication system

ABSTRACT

A wireless communication system transmits information requested by a wireless communication terminal to the wireless communication terminal moving through a spot wireless area. In a wireless base station, an external information communication control section controls communication with a server. A contents memory stores at least a part of contents received from the server. A wireless communication section communicates with the communication terminal using a predetermined communication method. A control section establishes connection with the communication terminal using a first connection which does not require an authentication procedure, or using a second connection which requires the authentication procedure. An access control (restriction) section permits access from the communication terminal to the contents memory and prohibits access to the server when a type of connection is the first connection, and permits access from the communication terminal to the contents memory and to the server in the case of the second connection.

This application is a divisional of application Ser. No. 12/504,806,filed Jul. 17, 2009.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wireless base station, a wirelesscommunication terminal, and a wireless communication system, and moreparticularly to a wireless base station, a wireless communicationterminal that establishes connection with the wireless base station, anda wireless communication system which perform communication in a spotcommunication area.

2. Description of the Related Art

In recent years, portable equipment equipped with a communicationfunction that meets the IEEE802.11 standard (hereinafter referred to asa wireless LAN communication function) is increasingly becomingwidespread. In addition, an area of use is not limited to an office or ahouse, but areas usable as a so-called hotspot are rapidly increasingoutdoors, although the area is an isolated spot communication area. Inresponse to this, wireless LAN is not only limitedly mounted on suchapparatuses as a personal computer or office equipment, but is alsomounted to various apparatuses, including household electricalappliances. Particularly, the wireless LAN is increasingly used invarious portable-type or in-vehicle type apparatuses such as a mobilephone.

In the IEEE802.11 standard, in order to establish connection between acommunication terminal and a wireless LAN base station, the followingbasic process is required. First, the communication terminal scans allcommunication channels so as to receive beacons periodically sent bywireless LAN base stations. Next, the communication terminal specifiescommunication channels of the wireless LAN base stations, determines awireless LAN base station desired to be connected, and decides whetheror not connection with the wireless LAN base station is permissible byusing an identifier, called an SSID (Service Set Identifier). Whenconnection is permissible, a communication path between the wireless LANbase station and the communication terminal is encrypted by using anencryption format typified by a WEP (Wired Equivalent Privacy), and aWPA (Wi-Fi Protected Access). Upon completion of recognition andencryption, the communication terminal finally becomes capable ofstarting communication with the wireless LAN base station.

In this manner, the IEEE802.11 standard has a feature that communicationis started upon completion of a series of connection processes includingcommunication channel scanning, detection of a wireless LAN basestation, authentication, and encryption. Two modes are defined ascommunication methods, that is, a unicast mode in which information istransmitted to specific communication terminals only by registeringaddresses of the communication terminals as destinations ofcommunication packets; and a broadcast mode in which information istransmitted to an indefinite number of communication terminals byregistering a broadcast address as the destination.

In the future, as a service using a wireless LAN-mounted apparatus, itis expected that a service having the following system will beincreasingly widely used. That is, wireless LAN base stations arelocated outdoors, and when a communication terminal passes through aspot communication area of one of the wireless LAN base stations,information is transmitted/received between the communication terminaland the wireless LAN base station. In the future, the communicationterminal will not be merely used in a semi-fixed state, but will be usedduring walking. In addition, it is expected that the communicationterminal will be increasingly used for high-speed movement such asmovement by bus or by train, or used for a car navigation systemequipped with a wireless LAN communication function. As the movementspeed of the communication terminal is increased, there is need forreduction in time elapsing from start of communication between thecommunication terminal and the wireless LAN base station to reception ofcontents from a server by the communication terminal, in addition toreduction in time necessary for a user operation. For example, manycommunication terminals are connected to a wireless LAN wireless basestation, a limited communication band is shared by a plurality ofcommunication terminals, and consequently a communication rate for eachcommunication terminal is lowered. As a result there may be a case wherea communication terminal hardly transmits/receive information duringpassing through a spot communication area.

It is expected that the number of communication terminal users will beincreased. Moreover, it is expected that data transmitted between anindividual communication terminal and a wireless LAN base station willbe dominated by such data having large capacity as audio data and visualdata rather than text only data. In order for a plurality ofcommunication terminals to receive such information during passingthrough the spot communication area, it has been needed a communicationmethod that exerts superior transmission efficiency.

Various countermeasures have been considered against the above-describedproblem. For example, disclosed in Japanese Laid-Open Patent PublicationNo. 2004-048395 (hereinafter, referred to as Patent Document 1) is aportable information terminal wireless LAN service so as to provide asystem that distributes information to a portable information terminalpassing through a communication area of a wireless LAN base station.FIG. 40 is a block diagram illustrating a configuration of aconventional portable information terminal wireless LAN service systemdisclosed in patent document 1. In FIG. 40, suppose that a portableinformation terminal (PDA) 2001 is owned by a user who, in advance,subscribes to an information service through a mobile phone, a PHS, orthe like.

The PDA 2001 has a WOR (Wake-on Ring: automatic activation) function,and in addition, has a wireless LAN client software installed thereon.An information provider 2004 is connected to a wake-on server 2005 and agate server 2002 which are controlled by an agent server 2003. In a spotcommunication area where information is provided, a wireless LAN basestation (not shown) is located so as to perform datatransmission/reception with a PDA 2001 owned by a user. When a userowning the PDA 2001 passes through the spot communication area, thewake-on server 2005 causes client software of the PDA 2001 to start. Theclient software of the PDA 2001 is connected to the gate server 2002 viathe wireless LAN base station, and information distributed from theinformation provider 2004 is stored in a memory of the PDA 2001.

However, even if the technology disclosed in Patent Document 1 is used,when it is assumed that a communication terminal moves in a spotcommunication area or the like at a high speed, time taken by thecommunication terminal to receive contents has not been sufficientlyreduced. In Patent Document 1, by having the client software started bythe wake-on server 2005, the user operation necessary for connection tothe wireless LAN base station has been improved. However, whether or notthe communication terminal has improved communication efficiency andwhether or not time elapsed until the contents are received are notdescribed therein.

As to the improvement in the communication efficiency, as describedabove, the broadcast mode is defined under the IEEE802.11 standard, andit is possible to transmit information simultaneously to a plurality ofcommunication terminals. When the broadcast mode of the wireless LAN isused, the information transmission efficiency is improved, however, thebase station is to transmit the same information to the plurality ofcommunication terminals regardless of whether or not the communicationterminals have requested for such transmission. Since memory capacity ofthe base station is limited, there is a possibility that contentsdesired by a communication terminal will not be transmitted thereto. Onthe other hand, since information requested by an indefinite number ofcommunication terminals is transmitted, unnecessary pieces ofinformation are also broadcasted. As a result, efficiency fortransmitting a piece of information requested by a communicationterminal is lowered.

BRIEF SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to solve theabove-described conventional problems, and to provide: a wireless basestation, which is capable of efficiently transmitting information to awireless communication terminal moving and passing through a spotcommunication area at a high speed, the information being requested bythe wireless communication terminal, by using broadcasting andcommunication in a combined manner, and is consequently capable oftransmitting/receiving a large amount of information; a wirelesscommunication terminal that establishes connection with the wirelessbase station; and a wireless communication system.

The present invention is directed to a wireless base station connectedto a server that distributes contents and to at least one wirelesscommunication terminal. To achieve the above-described object, thewireless base station of the present invention includes: an externalcommunication control section that controls communication with theserver; a contents memory section that stores at least a part of thecontents received from the server; an access restriction section thatmonitors a type of connection with the wireless communication terminal,and restricts access for connection from the wireless communicationterminal to the server or to the wireless base station; a wirelesscommunication section that communicates with the wireless communicationterminal in accordance with a predetermined communication method; and acontrol section that controls the wireless communication section. Thecontrol section controls the wireless communication section, andestablishes connection with the wireless communication terminal by usinga first connection which does not substantially require anauthentication procedure for connection with the wireless communicationterminal, or by using a second connection which requires theauthentication procedure for connection with the wireless communicationterminal. The access control (restriction) section permits access fromthe wireless communication terminal to the contents memory section andprohibits access from the wireless communication terminal to the serverwhen the type of connection with the wireless communication terminal isthe first connection, and permits access from the wireless communicationterminal to both of the contents memory section and the server when thetype of connection is the second connection.

Preferably, the contents memory section stores therein frequentlyrequested contents data that is frequently requested from the wirelesscommunication terminals, and individually requested contents data thatis less frequently requested as compared to the frequently requestedcontents data. In this case, an interval of the first connectionincludes a frequently requested contents data broadcasting interval andan individual contents data broadcasting interval. The control sectioncontrols the wireless communication section, and broadcastscollectively, to the wireless communication terminal, the frequentlyrequested contents data in the frequently requested contents databroadcasting interval, and transmits the individually requested contentsdata, which is requested by the wireless communication terminal, in theindividual contents data broadcasting interval.

The contents memory section further stores therein metadata relating tothe frequently requested contents data and to the individually requestedcontents data. In this case, the control section controls the wirelesscommunication section, and transmits the metadata to the wirelesscommunication terminals before the first connection is established, andreceives contents data request packets from the wireless communicationterminals in the interval of the first connection.

Further, the contents memory section stores therein frequently requestedcontents data that is frequently requested from the wirelesscommunication terminal, and individually requested contents data that isless frequently requested as compared to the frequently requestedcontents data. In this case, the control section may control thewireless communication section, and collect together and broadcast, tothe wireless communication terminals, the frequently requested contentsdata before the first connection is established, and transmit theindividually requested contents data, which is requested by the wirelesscommunication terminals, in the interval of the first connection.

Preferably, the contents memory section further stores therein metadatarelating to the frequently requested contents data and the individuallyrequested contents data. In this case, the control section controls thewireless communication section, and transmits the metadata to thewireless communication terminal before collecting together andbroadcasting, to the wireless communication terminals, the frequentlyrequested contents data, and receives contents data request packets fromthe wireless communication terminals in the interval of the firstconnection.

The contents memory section may partly interchange the frequentlyrequested contents data and the individually requested contents datawith each other in accordance with frequency of requests from thewireless communication terminals.

Preferably, the control section omits the authentication procedure inthe predetermined communication method in the case of using the firstconnection for connection with the wireless communication terminals, andexecutes the authentication procedure in the predetermined communicationmethod in the case of using the second connection for connection withthe wireless communication terminals.

The contents memory section stores therein contents that are notsubjected to access restriction.

The wireless base station may include a plurality of antennas. In thiscase, a plurality of wireless areas covered by the plurality of antennasare arranged so as to be at least partially overlapped with one another.Further, the contents memory section stores therein frequently requestedcontents data that is frequently requested by the wireless communicationterminals, and individually requested contents data that is lessfrequently requested as compared to the frequently requested contentsdata. In the case of contents transmission to the wireless communicationterminals, the wireless communication section: transmits the frequentlyrequested contents data to the wireless communication terminals from theplurality of antennas; and transmits the individually requested contentsdata to a certain wireless communication terminal via a correspondingantenna among the plurality of antennas, the antenna having received arequest from the wireless communication terminal.

Preferably, the wireless communication section includes: a firstwireless communication section that communicates with the wirelesscommunication terminals in accordance with a first wirelesscommunication method; and a second wireless communication section thatcommunicates with the wireless communication terminals in accordancewith a second wireless communication method. Prior to the first wirelesscommunication section starting communication with the wirelesscommunication terminals, the control section controls the secondwireless communication section, and transmits, to the wirelesscommunication terminals, profile information that is necessary for thefirst wireless communication section to communicate with the wirelesscommunication terminals.

The wireless base station may include at least one antenna for the firstwireless communication section and a plurality of antennas for thesecond wireless communication section. In this case, a wireless areacovered by the antenna for the first wireless communication section andwireless areas covered by the antennas for the second wirelesscommunication section are arranged so as to be at least partiallyoverlapped with one another.

Further, wireless base station may include a plurality of antennas forthe first wireless communication section and at least one antenna forthe second wireless communication section. In this case, wireless areascovered by the antennas for the first wireless communication section anda wireless area covered by the antenna for the second wirelesscommunication section are arranged so as to be at least partiallyoverlapped with one another.

Further, the present invention is directed to a wireless base stationtransmitting a signal to wireless communication terminals. The wirelessbase station of the present invention includes: a plurality of antennas;and a wireless communication section that communicates with the wirelesscommunication terminals by using the plurality of antennas in accordancewith a predetermined communication method. A plurality of wireless areascovered by the plurality of antennas are arranged so as to be at leastpartially overlapped with one another. The wireless communicationsection divides one information symbol into a first half portion and alatter half portion in transmitting a signal to the wirelesscommunication terminals, and transmits the former half portion and thelatter half portion including high-frequency signals, separately, viathe plurality of antennas as individual signals.

Further, the present invention is directed to a wireless communicationterminal connected, via a wireless base station, to a server thatdistributes contents. In order to achieve the above object, the wirelesscommunication terminal of the present invention includes: a wirelesscommunication section that communicates with the wireless base stationin accordance with a predetermined communication method; a controlsection that controls the wireless communication section; and a terminalcontrol section that controls transmission of information on a contentsrequest to the wireless base station. The control section controls thewireless communication section, and establishes connection with thewireless communication terminal by using a first connection which doesnot require an authentication procedure for connection with the wirelesscommunication terminal, or by using a second connection which requiresthe authentication procedure for connection with the wirelesscommunication terminal.

The wireless communication section receives metadata relating tocontents from the wireless base station. The terminal control sectionestablishes connection with the wireless base station by using the firstconnection, and transmits a contents data request packet to the wirelessbase station to request for contents data desired to be received, amongthe received metadata.

Preferably, the wireless communication terminal further includes acontrol-wireless communication section that performs communication inaccordance with a control-wireless communication method. In this case,the control section controls the control-wireless communication sectionprior to communication between the wireless base station and thewireless communication section, and obtains setting information so thatthe wireless base station and the wireless communication sectionperforms communication in accordance with the predeterminedcommunication method.

Further, the present invention is directed to a method implemented bythe above-described wireless base station and the wireless communicationterminal.

According to the present invention, it is possible to provide a wirelessbase station, which is capable of improving efficiency in transmittinginformation to wireless communication terminals passing through awireless spot communication area, so as to performtransmission/reception of a large amount of information, a wirelesscommunication terminal connected to the wireless base station, and awireless communication system. That is, it is possible for the wirelesscommunication terminal to reduce time elapsing until receiving contentssince the wireless base station caches contents information. Further,the wireless base station does not cache all pieces of information, butcaches a statistical result of requests by a communication terminal, andonly such information that is to be transmitted preferentially.Accordingly, a memory capacity can be saved. Further, the presentinvention has a configuration in which information frequently requestedby communication terminals is recognized, and contents thereof isbroadcasted in a fixed manner, whereas information of individuallyrequested contents data is interchanged and transmitted in accordancewith a request from the communication terminals. Accordingly, the basestation is required to interchange a transmission queue less frequently,and consequently, process time for transmission frame generation isreduced. Therefore, the transmission efficiency is improved, and as aresult, time elapsed until the wireless terminals receive contents canbe reduced.

These and other objects, features, aspects and advantages of the presentinvention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating an overall configuration of awireless communication system according to embodiment 1 of the presentinvention;

FIG. 2 is a diagram showing exemplary contents data;

FIG. 3 is a diagram showing exemplary operations performed in a secondconnection process according to embodiment 1 of the present invention;

FIG. 4 is a diagram showing exemplary operations performed in a firstconnection process according to embodiment 1 of the present invention;

FIG. 5 is a block diagram showing an exemplary configuration of anintegrated base station 101 according to embodiment 1 of the presentinvention;

FIG. 6 is a block diagram showing an exemplary configuration of acommunication terminal 201 according to embodiment 1 of the presentinvention;

FIG. 7 is a conceptual diagram showing a transmission sequencetransmitted from the integrated base station 101 according to embodiment1 of the present invention;

FIG. 8 is a diagram showing exemplary operations of the integrated basestation 101 according to embodiment 1 of the present invention;

FIG. 9 is a sequence diagram showing, in detail, data transmissionbetween the integrated base station 101 and communication terminals 201and 202 according to embodiment 1 of the present invention;

FIG. 10 is a diagram showing exemplary operations of the integrated basestation 101 according to embodiment 1 of the present invention;

FIG. 11 is a diagram showing exemplary operations of the communicationterminal 201 according to embodiment 1 of the present invention;

FIG. 12 is a diagram showing an exemplary frame format of metadata;

FIG. 13 is a diagram showing an exemplary frame format of the metadata;

FIG. 14 is a diagram showing an exemplary frame format of a contentsdata request packet;

FIG. 15 is a diagram showing an exemplary frame format of the contentsdata request packet;

FIG. 16 is a diagram showing exemplary tags;

FIG. 17 is a diagram showing a process performed after the integratedbase station 101 receives contents data request packets fromcommunication terminals 1 to N until contents are broadcasted;

FIG. 18 is a diagram showing a detailed transmission sequence of datatransmitted between the integrated base station 101 and thecommunication terminals 201 and 202;

FIG. 19A is a diagram showing a process flow in the case where acontents memory 11 in the integrated base station 101 is updated;

FIG. 19B is a diagram showing a process flow of datatransmission/reception in the integrated base station 101;

FIG. 20 is a diagram showing a process flow of datatransmission/reception in the communication terminal 201;

FIG. 21 is a schematic view illustrating an overall configuration of awireless communication system according to embodiment 2 of the presentinvention;

FIG. 22 is a diagram showing a transmission sequence of datatransmitted/received between an integrated base station 101 a and acommunication terminals 201 a and 202 a;

FIG. 23 is a diagram showing a flowchart of the integrated base station101 a according to embodiment 2 of the present invention;

FIG. 24 is a diagram showing a flowchart of the communication terminal201 a according to embodiment 2 of the present invention;

FIG. 25 is diagram showing an exemplary frame format of metadata;

FIG. 26 is a diagram showing an exemplary frame format of a contentsdata request packet;

FIG. 27 is a diagram showing a detailed transmission sequence of datatransmitted/received between the integrated base station 101 a and thecommunication terminals 201 a and 202 a;

FIG. 28 is a diagram showing a flowchart of the integrated base station101 a;

FIG. 29 is a diagram showing a flowchart of the communication terminal201 a;

FIG. 30 is a diagram showing an exemplary frame format of metadata;

FIG. 31 is a diagram showing an exemplary frame format of a contentsdata request packet;

FIG. 32 is a diagram showing a result of simulation of communicationrate required depending on the number of users of two-step broadcasting2 and two-step broadcasting 3;

FIG. 33 is a schematic diagram showing an overall configuration of awireless communication system according to embodiment 3 of the presentinvention;

FIG. 34 is a block diagram showing an exemplary configuration of anintegrated base station 101 b according to embodiment 3 of the presentinvention;

FIG. 35 is a block diagram showing an exemplary configuration of acommunication terminal 201 b according to embodiment 3 of the presentinvention;

FIG. 36A is a diagram showing an exemplary overall configurationaccording to embodiment 1 or 2 of the present invention in which anantenna section 113 is replaced with a plurality of antennas 1131 and1132;

FIG. 36B is a diagram showing an exemplary configuration of a wirelessLAN communication section which transmits/receives a signal using theplurality of antennas 1131 and 1132 shown in FIG. 36A;

FIG. 36C is a diagram showing an exemplary configuration of the wirelessLAN communication section which transmits/receives a signal using theplurality of antennas 1131 and 1132 shown in FIG. 36A;

FIG. 36D is a schematic diagram illustrating signals which aretransmitted simultaneously and are combined on a reception side;

FIG. 37 is a diagram showing an exemplary overall configurationaccording to embodiment 3 of the present invention in which an antennasection 114 is replaced with a plurality of antennas;

FIG. 38 is a diagram showing an exemplary overall configurationaccording to one of embodiments 1 to 3 of the present invention in whichthe antenna section is replaced with a plurality of antennas;

FIG. 39A is a diagram showing an exemplary overall configurationaccording to one of embodiments 1 to 3 of the present invention in whichthe antenna section is replaced with a plurality of antennas;

FIG. 39B is a diagram showing an exemplary configuration of acommunication section which transmits/receives a signal using aplurality of antennas shown in FIG. 39A; and

FIG. 40 is a block diagram showing a configuration of a conventionalwireless communication system.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, respective embodiments of the present invention will bedescribed with reference to drawings. Generally, in a wireless LANformat, communication between a wireless LAN base station and acommunication terminal may be started only after completion ofauthentication and encryption, which are connection procedures necessaryto perform in advance. In this situation, a connection which does notrequire authentication information such as a password before start ofcommunication and which allows any communication terminal to communicatewith a base station without substantially requiring authenticationprocedures is referred to as a first connection, whereas a connection,which requires the authentication procedures requiring authenticationinformation such as the password is referred to as a second connection.

Embodiment 1

FIG. 1 is a schematic view illustrating an overall configuration of awireless communication system according to embodiment 1 of the presentinvention. In FIG. 1, the wireless communication system includes anintegrated base station (wireless base station) 101, a wirelesscommunication terminal (hereinafter simply referred to as communicationterminal) 201, and a server 10. The integrated base station 101 isconnected to the server 10, which is capable of distributing informationrelating to various kinds of contents, by using wireless or wiredcommunication. The integrated base station 101 includes thereinside acontents memory 11 for storing therein contents. Further, the integratedbase station 101 is capable of mutually communicating with the server10, and has a function of caching the contents received from the server10 into the contents memory 11.

The communication terminal 201 is a communication terminal capable ofreceiving information while being moved, and is typified by a portableterminal, a PDA, a car navigation device, a PND (Personal NavigationDevice) that is a portable car navigation device, and the like, whichare hereinafter collectively referred to as a communication terminal.The communication terminal 201 establishes connection with theintegrated base station 101 by using a predetermined communicationmethod (typically, a wireless LAN communication), and in accordance withthe connection method, accessible information is restricted. In otherwords, when the integrated base station 101 is connected to thecommunication terminal 201 by using the first connection, thecommunication terminal 201 is able to receive information from thecontents memory 11 only. On the other hand, when the integrated basestation 101 is connected to the communication terminal 201 by using thesecond connection, the communication terminal 201 is able to receiveinformation from the contents memory 11 as well as from the server 10.

In the following description, an exemplary case where the communicationterminal 201 and the integrated base station 101 are connected to eachother by using the wireless LAN communication will be described. Thepresent invention, however, is applicable to all communication methodsin which the integrated base station 101 and the communication terminal201, which transmit and receive contents, operate independently of eachother, and are capable of performing spot communication. Therefore,although the explanation will be based on the wireless LAN system forconvenience, the present invention is not necessarily limited to thewireless LAN system. For example, a WiMAX in which stations are locatedso as to form a spot-type isolated wireless area, millimeter-wavecommunication in which communication is performed by using a millimeterwave, optical communication, and the like are also usable.

With reference to FIG. 2, a definition of contents will be described.The contents include metadata and contents data. The contents dataindicates contents of information service, and the metadata indicatesinformation relating to the contents data. When a television program isused as an example of contents, contents of a television programcorresponds to the contents data, and genre information such as “news”and “sport”, start time of a broadcast program, channel information, andthe like correspond to the metadata.

Further, with reference to FIGS. 3 and 4, the first connection and thesecond connection will be described. As shown in FIG. 3, the secondconnection is a mode in which the integrated base station 101 determines(authenticates) whether or not respective communication terminals 201are permitted to be connected thereto. As shown in FIG. 4, the firstconnection is a mode in which the integrated base station 101substantially permits all communication terminals 201 to be connectedthereto (open authentication, substantially no authentication), and isdesigned to simplify a procedure performed by the integrated basestation 101 for determining whether or not connection to thecommunication terminals 201 are permissible, and to reduce the timeelapsing until start of communication between the communicationterminals 201 and the integrated base station 101. Details will bedescribed later.

First, the second connection that is a typical authentication process inthe wireless LAN communication will be described. FIG. 3 is a sequencediagram illustrating a case where the communication terminal 201 isconnected to the integrated base station 101 by using the secondconnection. As shown in FIG. 3, the communication terminal 201 firstperforms channel search in order to search for a communication channelof the integrated base station 101 (step all). During the channelsearch, the communication terminal 201 monitors all channels for apredetermined period of time, and receives a beacon from the integratedbase station 101, thereby confirming the presence of the integrated basestation 101 having the channel.

The communication terminal 201 receives the beacon transmitted from theintegrated base station 101 (step a01). The beacon includes an SSIDtransmitted from the integrated base station 101. The communicationterminal 201 transmits, to the integrated base station 101, the SSIDprovided to the beacon, that is, a probe request for requesting start ofconnection (step a02). Upon reception of the probe request, theintegrated base station 101 transmits a probe reply to the communicationterminal 201 (step a03).

Next, the communication terminal 201 transmits an authentication requestto the integrated base station 101 in order to obtain authenticationpermission from the integrated base station 101 (step a04). Uponreception of the authentication request, the integrated base station 101performs a determination process for determining whether or notconnection to the communication terminal 20 that has performed theauthentication request is permissible. For example, in the wireless LANcommunication, the determination process for connection permission isperformed through an exchange of an encrypted message. Specifically, theintegrated base station 101 transmits a random value called “challenge”to the communication terminal 201 (step a05).

Next, the communication terminal 201 encrypts the challenge by using anencryption key, and transmits the encrypted challenge response to theintegrated base station 101 (step a06). Upon reception of the encryptedchallenge response, the integrated base station 101 decodes theencrypted challenge, and when the decoded challenge corresponds to itsoriginal challenge, connection of the communication terminal 201 ispermitted. Based on the series of procedures, the integrated basestation 101 determines whether or not connection to the communicationterminal 201 is permissible, and when the connection is permitted, theauthentication response is transmitted to the communication terminal 201(step a07).

In FIG. 3, an authentication operation for determining whether or notconnection to the communication terminal 201 is permissible is referredto as an authentication process. In the authentication process, when theintegrated base station 101 determines that connection is permissible,the communication terminal 201 performs an association request forestablishing logical connection with the integrated base station 101(step a08). On the other hand, the integrated base station 101 returnsan association reply (step a09). Upon completion of association, thecommunication terminal 201 and the integrated base station 101 are ableto start communication (step a10).

Next, FIG. 4 a sequence diagram showing a case where the communicationterminal 201 is connected to the integrated base station 101 by usingthe first connection. In the first connection, unlike the secondconnection, upon reception of an authentication request from thecommunication terminal 201, the integrated base station 101 promptlyreturns an authentication response. In FIG. 4, authentication betweenthe authentication request in step a04 and the authentication responsein step a07 is referred to as an open authentication. The firstconnection is a simple connection method in which the authenticationprocess of the second connection is replaced with the openauthentication. Although the open authentication is referred to as“authentication”, the integrated base station 101 promptly returns theauthentication response upon reception of the authentication request, asabove described, and thus permits connection of all communicationterminals 201 substantially without authentication. Therefore, in theauthentication process of the second connection shown in FIG. 3, theintegrated base station 101 needs time for various significant processesfor strictly determining whether or not connection with thecommunication terminal 201 is permissible. On the other hand, the firstconnection does not perform such processes, and thus it is possible toreduce time elapsing from start of connection to start of communicationas compared to the second connection.

FIG. 5 is a block diagram showing an exemplary configuration of theintegrated base station 101 according to embodiment 1 of the presentinvention. As shown in FIG. 5, respective sections in the integratedbase station 101 are connected via a system bus, and are capable oftransferring data mutually. An external information communicationsection 102 transfers contents information from the server 10 to amemory section, or conversely transfers information from the memorysection 103 to the server 10 by using a wired communication technologysuch as Ethernet (registered trademark) or the like.

Note that, in the present invention, the external informationcommunication section 102 of the integrated base station 101communicates with the server 10, and the communication need not beperformed in a wired manner by using Ethernet (registered trademark),for example. Instead, communication with the server 10 may be performedby using a wireless LAN, an FWA (Fixed Wireless Access), and the like.Accordingly, flexibility in installing the integrated base station 101can be improved.

The base station control section 120 includes an access restrictionsection 121 and a contents memory section 122. The access restrictionsection 121 monitors a connection type of the communication terminal 201connected to the integrated base station 101, and permits access fromthe communication terminal 201 to the server 10 and the contents memorysection 122 when the connection type is the second connection. On theother hand, when the connection type is the first connection, the accessrestriction section 121 prohibits access from the communication terminal201 to the server 10, and only permits access therefrom to the contentsmemory section 122. The contents memory section 122 mainly caches highlypublic contents among contents included in the server 10. The highlypublic contents are, for example, town tourist information, storeinformation, news information, whether information, traffic information,and the like. That is, the contents memory section 122 mainly storestherein contents which are not subjected to access restriction as aresult of the authentication of the communication terminal 201. Further,in order to reduce the connection time, the contents memory section 122may stores therein contents that are very frequently requested from thecommunication terminal 201.

A control section 104 includes a communication control section 123, anda wireless LAN control section 108. The communication control section123 is a section for controlling the whole of the integrated basestation 101, and includes a profile information control section 115, acommunication control information storage section 126, a receivingbuffer section 215, and a transmitting buffer section 219. The profileinformation control section 115 is designed to store therein information(profile information) necessary for the communication terminal 201 toestablish connection through communication with the wireless LANcommunication section 105.

Here, the profile information will be described. The profile informationis a communication channel, identification information (e.g., BSSID),encryption information (e.g., a WEP key) and the like of the wirelessLAN control section 108. The profile information is not limited to theabove-described information as long as the information is designed tofacilitate high-speed simple connection with the wireless LAN controlsection 108.

The communication control information storage section 126 stores thereinan instruction set for controlling the wireless LAN control section 108.A receiving buffer section 215 is used for buffering informationreceived by the wireless LAN control section 108. In a similar manner,the transmitting buffer section 219 is used for buffering information tobe transmitted by using the wireless LAN control section 108.

The wireless LAN control section 108 is a section to control thewireless LAN, and includes a frame generation and transmission/receptioncontrol section 125. The wireless LAN communication section 105 includesa transmitting section 106, a receiving section 107, and an antennasection 113. A wireless LAN startup information storage section 501 hasinformation for starting the wireless LAN communication section of thecommunication terminal 201, and attaches wireless LAN startupinformation to a packet to be transmitted to the communication terminal201.

FIG. 6 is a block diagram showing an exemplary configuration of thecommunication terminal 201 according to embodiment 1 of the presentinvention. As shown in FIG. 6, respective sections in the communicationterminal 201 are connected via a system bus, and thus are able totransfer data mutually. The communication terminal 201 includes acontrol section 802, a wireless LAN communication section 804, a memorysection 220, an input section 217, a terminal control section 227, adisplay section 218, and a sensor section 228.

The wireless LAN communication section 804 includes a transmittingsection 207, a receiving section 208, an antenna section 209, and awireless LAN power supply section 807. The control section 802 includesa communication control section 226 and a wireless LAN control section805. The communication control section 226 controls the wireless LANcontrol section 805. The wireless LAN control section 805 includes awireless LAN power supply control section 806, a profile informationsetting section 205, and a frame generation and transmission/receptioncontrol section 225. The profile information setting section 205obtains, from a profile information storage section 214, profileinformation of a wireless LAN to be connected, and sets connectioninformation for its own wireless LAN communication.

The memory section 220 is used for storing and buffering data of thecommunication terminal 201. The memory section 220 includes a profileinformation storage section 214, a communication control informationstorage section 223, a receiving buffer section 215, and a transmittingbuffer section 219. The profile information storage section 214 storestherein information (i.e., profile information and the like) which isreceived by the communication terminal 201 and is necessary forconnection with the integrated base station 101. Further, thecommunication control information storage section 223 stores therein aninstruction set necessary for the communication terminal 201 to performcommunication. The input section 217 is a section to which a useroperation is inputted.

The terminal control section 227 is a section for controlling a terminalfunction of the communication terminal 201, and includes a requestcontents filter section 221, a display control section 216, and a userattribute extraction section 222. The display control section 216controls information displayed on a display section 218 of thecommunication terminal 201. The user attribute extraction section 222extracts an attribute and a preference of a user (hereinafter referredto as user attribute information) in accordance with information from asensor section 228. The request contents filter section 221 filtersmetadata received from the integrated base station 101 so as to obtaincontents that coincide with the user in accordance with the userattribute information extracted by the user attribute extraction section222. Request information obtained through filtering by the requestcontents filter section 221 is transmitted from the communicationterminal 201 to the integrated base station 101. Accordingly, thecommunication terminal 201 receives information that strongly correlateswith the preference of the user of the terminal.

FIG. 7 shows a schematic diagram of a transmission sequence from theintegrated base station 101. One of the features of the presentinvention is that depending on whether connection between thecommunication terminal 201 and the integrated base station 101 isestablished by using the first connection or the second connection,information accessible by the communication terminal 201 is restricted.Accordingly, the integrated base station 101 also needs to havecommunication intervals using these two connections. As shown in FIG. 7,the integrated base station 101 is configured so as to repeat thecommunication interval using the first connection and the communicationinterval using the second connection. The two communication intervalsneed not have fixed time lengths, and may be changed dynamically. Thatis, when there is a plurality of the communication terminals 201performing communication with the integrated base station 101, and mostof the communication terminals use the first connection, then it ispossible to set the length of the communication interval using the firstconnection longer. Accordingly, it is possible to effectively utilize acommunication band.

With reference to FIG. 8, a process flow of the integrated base station101 (FIG. 6) will be described. As shown in FIG. 8, the integrated basestation 101 receives a request packet from the communication terminal201 (step S502). Next, the access restriction section 121 checks aconnection method for connecting with the communication terminal 201(step S503). When connection with the communication terminal 201 isestablished by using the second connection, the integrated base station101 sets such that the communication terminal 201 is accessible to bothof the contents memory section 122 and the server 10 (step S505). Whenthe connection with the communication terminal 201 is established byusing the first connection, the integrated base station 101 sets suchthat the communication terminal 201 is accessible to the contents memorysection 122 only (step S506).

Here, a method for checking, by the access control (restriction) section121, the connection method for connecting with the communicationterminal 201 and will be described. Various methods may be considered asthe method for checking, by the access control (restriction) section121, the connection method for connecting with the communicationterminal 201. For example, the integrated base station 101 preferablystores, in the access restriction section 121 or the like, a MAC addressof a communication terminal to be connected thereto and the connectionmethod, so as to identify the connection method for connection with thecommunication terminal 201 in accordance with a MAC address of a sourceof a received packet (i.e., the MAC address of the communicationterminal 201).

Further, a method may be used in which the integrated base station 101has an SSID for the first connection and an SSID for the secondconnection, such that the communication terminal 201 selects the SSIDfor connection with the integrated base station 101 in accordance withthe first connection and the second connection. Still further, bypreparing individual encryption keys (e.g., a WEP key or the like) forthe first connection and the second connection, it may be possible forthe integrated base station 101 to determine whether the communicationterminal 201 has sent a packet by using the first connection or thesecond connection.

The access control (restriction) section 121 may check the connectionmethod for connecting with the communication terminal 201 by using theabove-described methods in a combined manner, or need not necessarilyuse the methods. For example, the access restriction section 121 maydetermine that the first connection is used for the connection with thecommunication terminal 201 when contents of a request packet requestedby the communication terminal 201 is stored in the contents memorysection 122. On the other hand, the access restriction section 121 maydetermine that the second connection is used for the connection with thecommunication terminal 201 when the contents of the request packetrequested by the communication terminal 201 is not stored in thecontents memory section 122, but in the server 10.

Alternatively, the communication terminal 201 may determine, based onmetadata received thereby, the connection method for connection with theintegrated base station 101, whereas the access control (restriction)section 121 may determine whether the first connection or the secondconnection is used in accordance with the connection method determinedby the communication terminal 201. In this case, the communicationterminal 201 is able to identify, based on the received metadata,whether the requested contents are stored in the integrated base station101 or in the server 10. When the requested contents are stored in theintegrated base station 101, the communication terminal 201 establishesconnection with the integrated base station 101 using the firstconnection. On the other hand, when the requested contents are stored inthe server 10, the communication terminal 201 establishes connectionwith the integrated base station 101 using the second connection.

Further, another feature of the present invention is that the integratedbase station 101 efficiently transmits information while combiningbroadcasting and communication. FIG. 9 shows, in detail, a datatransmission sequence in the present invention. In FIG. 9, data 609 and614 indicated with ellipses is data transmitted from the integrated basestation 101 by using broadcasting. The communication intervals 604 and608 are each an interval using the second connection. First, theintegrated base station 101 broadcasts the metadata 609 in a metadatatransmission interval 601 to a communication terminal 201 and acommunication terminal 202. The communication terminals 201 and 202process the received metadata 609 in their request contents filtersections 221, so as to determine contents data to be requested. Thecommunication terminals 201 and 202 transmit and receive, to and fromthe integrated base station 10, data 610 and 612 used in a firstconnection process and requests 611 and 613 for contents data. Theintegrated base station 101 collects the requested contents data in acontents data transmission interval 603, and broadcasts contents data614 requested as a result of the collection.

FIG. 10 shows an exemplary operation performed by the integrated basestation 101, in which broadcasting and communication are combinedtogether. As shown in FIG. 9 and FIG. 10, the integrated base station101 transmits metadata 609 in metadata transmission intervals 601 and605 (step S702). Next, the integrated base station 101 establishes, byusing the first connection, connection with the communication terminal201 which has received the metadata 609 (step S703). The integrated basestation 101 receives contents data request packets 611 and 613transmitted from the communication terminal 201 in the contents datarequest intervals 602 and 606 (step S704), and summarizes the contentsdata request packets so as to generate data to be transmitted (stepS705). The integrated base station 101 then transmits the contents data614 in contents data transmission intervals 603 and 607 (step S706).

Next, when there is a communication terminal 201 requesting a secondconnection process in normal communication intervals 604 and 608, theintegrated base station 101 performs the second connection process forconnection with the communication terminal 201 (step S708), and performsnormal wireless LAN communication (step S709). When there is nocommunication terminal 201 requesting the second connection process inthe communication intervals 604 and 608, the process is terminated.

FIG. 11 shows a process flow of the communication terminal 201. As shownin FIG. 9 and FIG. 11, the communication terminal 201 receives metadatafrom the integrated base station 101 in metadata transmission intervals601 and 605 (step S802). Next, the communication terminal 201determines, in its request contents filter section 221, contents desiredto be received, and stores a list of contents data requests in atransmission buffer (step S803). The communication terminal 201 thenperforms the first connection process for connection with the integratedbase station 101 in the contents data request intervals 602 and 606(step S804), and transmits a contents data request packet to theintegrated base station 101 (step S805). Next, the communicationterminal 201 receives contents data from the integrated base station 101in the contents data transmission intervals 603 and 607 (step S806). Inthe case of requiring more personal information and detailedinformation, the communication terminal 201 performs normalcommunication with the integrated base station 101. In the case ofperforming the normal communication (Yes in step S807), thecommunication terminal 201 performs the second connection process forconnection with the integrated base station 101 (step S808), so as tostart the normal communication (step 809). In the case of no normalcommunication being performed, the process is terminated.

FIG. 12 shows a frame format of metadata transmitted from the integratedbase station 101. As shown in FIG. 12, the metadata transmitted from theintegrated base station 101 generally includes data equivalent to aplurality of contents. Metadata corresponding to certain contents hasadded thereto a contents ID and a tag corresponding to the contents ID.

The frame format of the metadata is not necessarily limited to such aformat shown in FIG. 12 as long as the frame format includes thecontents ID and the tag indicative of meta information. For example, aframe format shown in FIG. 13 may be applicable. As shown in FIG. 13, alist of metadata of contents transmitted from the integrated basestation 101 is transmitted, and then contents IDs and index informationof tags may be added. Accordingly, duplicated tags are not transmittedin a duplicated state, which contributes to reduction in an amount ofdata to be transmitted.

FIG. 14 shows an exemplary frame format of a contents data requestpacket transmitted by the communication terminal 201 to the integratedbase station 101. With reference to FIG. 14, the integrated base station101 transmits requesting contents IDs to the integrated base station101. In the case of requesting normal data, the communication terminal201 uses a URL request or the like. However, by assigning ID numbers tocontents data cached in the integrated base station 101, it is possibleto significantly reduce an amount of data requested by the communicationterminal 201.

The communication terminal 201 need not necessarily use the contents IDfor performing contents data request. Instead, as shown in FIG. 15, forexample, tags may be used for contents request. Accordingly, in additionthat the amount of information of request packets transmitted by thecommunication terminal 201 is reduced, the communication terminal 201 isable to determine contents desired to be received, in accordance withthe tag, instead of individual contents. Thus, it is possible to reducetime required for filtering for obtaining contents to be requested.

FIG. 16 shows exemplary tags. The tag is different from a category inthat use of the tag enables addition of a plurality of pieces ofattribute information to one piece of information. For example, to movieinformation, “news” and “entertainment” tags may be added, and torestaurant information, “coupon” and “restaurant” tags may be added.Tags are added to contents, and request for desired contents areperformed accordingly, whereby it is possible to request contentssuitable to a preference of a user of the communication terminal 201while a load of a filtering process placed on the communication terminal201 is reduced.

With reference to FIG. 17, processing from reception of contents datarequest packets from communication terminals 201 to 20N through tobroadcasting of the contents, performed by the integrated base station101,will be described. The communication terminals 201 to 20N requestfor tags of their desired contents, respectively. Here, suppose that thecommunication terminal 201 requests for “tag A” and “tag B”, thecommunication terminal 202 requests for “tag A”, “tag C”, and “tag D”,and the communication terminal 20N requests for “tag A” and “tag D”. Theintegrated base station 101 summarizes tags requested by thecommunication terminals 201 to 20N, and refers to a table owned thereby.As a result of the summary, the tags requested by the communicationterminals 201 to 20N are “tag A”, “tag B”, “tag C”, and “tag D”, andthus contents to be transmitted are “contents 1”, “contents 2”,“contents 3”, “contents 4”, and “contents 5”. The integrated basestation 101 broadcasts the summarized contents.

In this manner, the integrated base station 101 summarizes requestinformation from the respective communication terminals 201 to 20N, andbroadcasts contents corresponding to the summarized request information,whereby it is possible to minimize an amount of data for transmittinginformation requested by all the communication terminals 201 to 20N.

As shown in FIG. 18, the integrated base station 101 may be configuredso as to broadcast a fixed amount of contents without receiving anyrequest from the communication terminals 201 and 202. In FIG. 18, data609 and 1501 indicated with ellipses is data transmitted from theintegrated base station 101 by using broadcasting. The integrated basestation 101 broadcasts metadata 609 to the communication terminal 201and the communication terminal 202 in the metadata transmissionintervals 601 and 605. In this case, the integrated base station 101performs broadcasting including metadata of contents that are not cachedin the contents memory 11. Next, the integrated base station 101broadcasts the contents data 1501 to the communication terminal 201 andthe communication terminal 202 in the contents data transmissionintervals 603 and 606. The communication terminals 201 and 202 receive,through individual communication, contents that are not broadcasted innormal communication intervals 604 and 608. Specifically, thecommunication terminals 201 and 202 transmit and receive data 1502 and1505 used for the first connection process and contents data requestpackets 1503 and 1506 to and from the integrated base station 101. Theintegrated base station 101 transmits individually requested contentsdata 1504 and 1507 to the communication terminals 201 and 202.

Next, a method for determining contents to be broadcasted by theintegrated base station 101 in contents data transmission intervals 603and 606 will be described. In the contents data transmission intervals603 and 606 in the integrated base station 101, it is preferable tobroadcast contents data very frequently requested by the communicationterminals 201 and 202. This is because frequency of individual requestsof the contents data is reduced in the normal communication intervals604 and 608. Data broadcasted by the integrated base station 101 in thecontents data transmission intervals 603 and 606 includes contents datafrequently requested by the communication terminals 201 and 202 in thenormal communication intervals 604 and 608, in addition to contents datato be transmitted by all means such as town notice, emergencyinformation, and the like. Probability that contents data, among allcontents data, requested by the communication terminals 201 and 202 aretransmitted in the contents data transmission intervals 603 and 606, isdefined as a hit rate. In this situation, when information, which isfrequently requested by the communication terminals 201 and 202individually in the normal communication intervals 604 and 608, isbroadcasted in the contents data transmission intervals 603 and 606, itis possible to raise the hit rate.

FIG. 19A shows a flow chart of updating of the contents memory 11 in theintegrated base station 101, based on the method illustrated in FIG. 18.As shown in FIG. 19A, the integrated base station 101 receives from theserver 10 contents to be cached in the contents memory 11 (step S1602).Next, the integrated base station 101 determines whether or not toupdate the contents, and receives the contents again from the server 10in the case of updating the contents to be cached (Yes in step S1603).On the other hand, in the case of not updating the contents, the processis terminated (step S1604). Determination of whether or not to updatethe contents is preferably performed regularly, but is not necessarilyperformed so. Alternatively, a configuration may be possible in whichwhen contents being cached is updated on the server 10, the server 10provides a trigger, such that the contents being cached in theintegrated base station 101 is updated.

FIG. 19B shows a flow chart of data transmission/reception performed onthe integrated base station 101, based on the method illustrated in FIG.18. As shown in FIG. 18 and FIG. 19B, the integrated base station 101transmits metadata 609 in metadata transmission intervals 601 and 605(step S1702). Next, the integrated base station 101 transmits contentsdata 1501 in contents data transmission intervals 603 and 606 (stepS1703) by using broadcasting. Then, the integrated base station 101performs the second connection process for connection with thecommunication terminals 201 and 202 (step S1704), and receives contentsdata request packets 1503 and 1506 transmitted from the communicationterminals 201 and 202 (step S1705). Thereafter, the integrated basestation 101 transmits contents data 1504 and 1507 in accordance with arequest packet 1503 and 1506 (step S1706). Further, the integrated basestation 101 transmits request information to the server 10 in order toimprove the hit rate (step S1707).

FIG. 20 shows a flow chart of data transmission/reception performed onthe communication terminal 201, based on the method illustrated in FIG.18. As shown in FIG. 18 and FIG. 20, the communication terminal 201receives the metadata 609 from the integrated base station 101 in themetadata transmission intervals 601 and 605 (step S1802). Next, thecommunication terminal 201 determines, in its request contents filtersection 221, contents desired to be received, and stores a list ofcontents data requests in a transmission buffer (step S1803). Next, thecommunication terminal 201 receives contents data 1501 in the contentsdata transmission intervals 603 and 606 (step S1804). Then communicationterminal 201 performs, in the normal communication intervals 604 and608, the second connection process for connection with the integratedbase station 101 in order to receive, in contents data transmissionintervals 603 and 606, contents data yet to be broadcasted (step S1805),and transmits a contents data request packet 1503 to the integrated basestation 101 (step S1806). As a result, the communication terminal 201finally receives contents data 1504 that is yet to be broadcasted orreceived, in the normal communication interval 604 and 608, from theintegrated base station 101 (step S1807).

As described above, according to the present invention, when theintegrated base station 101 is connected to the communication terminal201 by using the first connection, the communication terminal 201 isable to obtain contents stored in the contents memory 11. On the otherhand, when the integrated base station 101 is connected to thecommunication terminal 201 by using the second connection, thecommunication terminal 201 is able to obtain contents stored in both thecontents memory 11 and the server 10. That is, switching between thefirst connection and the second connection enables reduction in timenecessary for the communication terminal 201 to obtain contents whilemaintaining security.

Embodiment 2

FIG. 21 is a schematic view illustrating an overall configuration of awireless communication system according to embodiment 2 of the presentinvention. In FIG. 21, the wireless communication system includes anintegrated base station 101 a, a communication terminal 201 a, and aserver 10. In FIG. 21, a solid arrow shows a flow of communication data,and a broken arrow shows a flow of broadcast data. The integrated basestation 101 a has metadata 1906, frequently requested contents data1907, and individually requested contents data 1908 stored in itscontents memory 11.

In comparison with embodiment 1, embodiment 2 has a feature that thecontents data accumulated in the contents memory 11 of the integratedbase station 101 a is divided into frequently requested contents data1907 which is relatively frequently requested, and individuallyrequested contents data 1908 which is relatively less frequentlyrequested. The individually requested contents data 1908 is transmittedupon request from the communication terminal 201 a. Accordingly, theinvention according to embodiment 2 can achieve reduction in timenecessary for the integrated base station 101 a to perform atransmission data generation process, while a high hit rate ismaintained. Since basic configurations of the integrated base station101 a and the communication terminal 201 a are the same as those shownin embodiment 1, common reference numerals will be applied to commonsections, and description thereof will be omitted.

Among the contents data included in the contents memory 11, thefrequently requested contents data 1907 is such contents data that istransmitted regardless of the degree of frequency of requests, and is,for example, contents data that is frequently requested from thecommunication terminal 201 a, town information, emergency information,and disaster information. Such contents data is, statistically, highlylikely to be requested by the communication terminal 201 a, and thus istransmitted regardless of whether or not a request for the contents datais made by the communication terminal 201 a at a certain time point.Accordingly, the frequency for changing an arrangement of a transmissionqueue of the frequently requested contents data 1907 is lower than thatfor the individually requested contents data 1908.

The individually requested contents data 1908 is such contents data thatis less frequently requested by the communication terminal 201 a ascompared to the frequently requested contents data 1907. The metadata1906 includes metadata of the frequently requested contents data 1907and the individually requested contents data 1908. The communicationterminal 201 a grasps contents data in the contents memory 11 by meansof the metadata 1906. Based on the frequently requested contents data1907, the communication terminal 201 a receives contents data which isstatistically frequently requested by many users. Thereafter, thecommunication terminal 201 a receives, as the individually requestedcontents data 1908, contents data that is not able to be received as thefrequently requested contents data 1907 in spite of a contents datarequest made in a contents data request interval.

Hereinafter, details will be described. FIG. 22 is a diagram showing atransmission sequence of data transmitted between the integrated basestation 101 a and the communication terminals 201 a and 202 a accordingto embodiment 2. A method used for the data transmission is referred toas a two-step broadcasting A method. In FIG. 22, data 1906, 1907, and1908 indicated with ellipses is data transmitted from the integratedbase station 101 a by using broadcasting.

The integrated base station 101 a has a metadata transmission interval2001, a contents data request interval 2002, a contents transmissioninterval 2003, and a normal communication interval 2006. Further, thecontents transmission interval 2003 includes a frequently requestedcontents data broadcasting interval 2004 and an individual contents datatransmission interval 2005.

FIG. 23 shows a flowchart of the integrated base station 101 a accordingto embodiment 2. As shown in FIGS. 22 and 23, the integrated basestation 101 a transmits metadata 1906 to communication terminals 201 aand 202 a in the metadata transmission interval 2001 (stepS2101). Next,the integrated base station 101 a performs a first connection processfor connection with the communication terminals 201 a and 202 a in thecontents data request interval 2002 (stepS2102), and receives contentsdata request packets 2009 and 2011 from the communication terminals 201a and 202 a (stepS2103).

The integrated base station 101 a broadcasts the frequently requestedcontents data 1907 to the communication terminals 201 a 202 a in thefrequently requested contents data broadcasting interval 2004(stepS2104). Next, the integrated base station 101 a performs anindividually requested contents data generation process in theindividual contents data transmission interval 2005 (stepS2105), andtransmits the generated individually requested contents data 1908 to thecommunication terminals 201 a and 202 a (stepS2106). The integrated basestation 101 a then determines whether or not to perform normalcommunication with the communication terminals 201 a and 202 a in thenormal communication interval 2006 (stepS2107). In the case ofperforming the normal communication, the integrated base station 101 aperforms the second connection process for connection with thecommunication terminals 201 a and 202 a to perform the normalcommunication (stepS2109). In the case of not performing the normalcommunication (No in stepS2107), the integrated base station 101 a endsthe processing (step S2110).

FIG. 24 shows a flowchart of the communication terminal 201 a accordingto embodiment 2. As shown in FIGS. 22 and 24, the communication terminal201 a first receives the metadata 1906 from the integrated base station101 a during the metadata transmission interval 2001 (stepS2201). Thecommunication terminal 201 a selects, based on the received metadata1906, contents data desired to be received (stepS2202). Thecommunication terminal 201 a then performs the first connection processfor connection with the integrated base station 101 a in the contentsdata request interval 2002 (stepS2203), and transmits the contents datarequest packet 2009 (stepS2204).

Next, the integrated base station 201 a receives the frequentlyrequested contents data 1907 in the frequently requested contents databroadcasting interval 2004 (stepS2205), and receives the individuallyrequested contents data 1908 in the individual contents datatransmission interval 2005 (stepS2206). The communication terminal 201 athen determines whether or not to perform normal communication with theintegrated base station 101 a (stepS2207). In the case of performing thenormal communication, the communication terminals 201 a performs thesecond connection process for connection with the integrated basestation 101 a (stepS2208) and performs the normal communication(stepS2209). In the case of not performing the normal communication (Noin stepS2207), the communication terminal 201 a terminates theprocessing (stepS2110).

FIG. 25 shows a frame format of metadata transmitted from the integratedbase station 101 a. As shown in FIG. 25, the metadata transmitted fromthe integrated base station 101 a generally includes data of a pluralityof contents. Metadata corresponding to certain contents includes acontents ID, a tag corresponding to the contents ID, and transmissionidentification information. The transmission identification informationincludes bit information for identifying whether or not contents datacorresponding to the contents ID is to broadcast in the frequentlyrequested contents data broadcasting interval 2004.

FIG. 26 shows a frame format of a contents data request packet to betransmitted to the integrated base station 101 a by the communicationterminal 201 a. With reference to FIG. 26, the communication terminal201 a basically specifies contents data desired to be received by usinga tag. Further, when the contents data desired to be received isscheduled to be received in the frequently requested contents databroadcasting interval 2004 at a later time, the communication terminal201 a sets an identification flag on a tag reception flag so as toindicate that the contents are desired to be received and is to bereceived later.

Accordingly, the integrated base station 101 a is able to identifycontents data having a high hit rate and contents data having a low hitrate, among the frequently requested contents data 1907. Thus, theintegrated base station 101 a is able to replace, in the frequentlyrequested contents data 1907, contents data having a low hit rate withcontents data requested very frequently.

Generally, a contents request made by users tends to be focused onspecific contents. In accordance with embodiment 2, the contents datafrequently requested by users is broadcasted in a fixed manner in thefrequently requested contents data broadcasting interval 2004, whereasthe remaining contents are broadcasted in the individual contents datatransmission interval 2005, whereby an amount of contents, in thetransmission queue, to be replaced by the integrated base station 101 ais reduced. Accordingly, it is possible to reduce waiting time untildata transmission.

Above described configuration in embodiment 2 is an example in which thecontents data request interval 2002 is provided, and based oninformation requested in the interval, the frequently requested contentsdata 1907 is broadcasted in the frequently requested contents databroadcasting interval 2004. However, the present invention is notlimited to the configuration. For example, a configuration as shown inFIG. 27 may be applicable in which the integrated base station 101 adoes not have the contents data request interval 2002, and receivescontents data requests 2009 and 2011 in the individual contents datatransmission interval 2005 a. The communication terminals 201 a and 202a individually requests, in the individual contents data transmissioninterval 2005 a, for contents data which has not been broadcasted in thefrequently requested contents data broadcasting interval 2004. This typeof method is referred to as a two-step broadcasting B method.Accordingly, the integrated base station 101 a does not need collect thecontents data together to generate a frame for broadcasting inaccordance with the requests from the communication terminals 201 a and202 a. Thus, reduction in a load on the integrated base station 101 acan be expected.

FIG. 28 shows a flowchart of the integrated base station 101 a in theabove-described method. As shown in FIGS. 27 and 28, the integrated basestation 101 a transmits metadata (stepS2101), and broadcasts thefrequently requested contents data 1907 in the frequently requestedcontents data broadcasting interval 2004 (stepS2601). Next, theintegrated base station 101 a performs the first connection process forconnection with the communication terminals 201 a and 202 a in theindividual contents data transmission interval 2005 a (stepS2102), andreceives contents data request packets 2009 and 2011 from thecommunication terminals 201 a and 202 a (stepS2602). The integrated basestation 101 a transmits the individually requested contents data 1908 aand 1908 b corresponding to the requests (stepS2603).

FIG. 29 shows a flowchart of the communication terminal 201 a. As shownin FIGS. 27 and 29, after selection of contents desired to be received,the communication terminal 201 a receives the frequently requestedcontents data 1907 in the frequently requested contents databroadcasting interval 2004 (stepS2701). Next, the communication terminal201 a performs the first connection process for connection with theintegrated base station 101 a in the individual contents transmissioninterval 2005 a (stepS2203), transmits a contents data request packet2009 (stepS2702), and receives the individually requested contents data1908 a (stepS2703).

In embodiment 2 of the present invention, the frame format of themetadata transmitted from the integrated base station 101 a is notlimited to the format shown in FIG. 25. For example, as shown in FIG.30, the frame format is configured such that tags are listed, and thenindex information, i.e., ID information of a tag included in contents,and the index information together with contents ID are added to thelist of tags. Accordingly, tags of contents can be concentratedtogether, and consequently reduction in an amount of transmission datacan be expected.

Further, the contents data request packet transmitted by thecommunication terminal 201 a to the integrated base station 101 a is notnecessarily limited to a configuration in which a request for receivingdesired contents data is based on the tags as shown in FIG. 26. Instead,as shown in FIG. 31, the contents data request packet may be configuredsuch that a request for receiving desired contents data is based on theindividual contents IDs. Accordingly, the communication terminal 201 ais able to appropriately specify information that is highly preferred bythe user, and to perform a request for contents transmission.

FIG. 32 shows a result of simulation of communication rates requireddepending on the number of users using the two-step broadcasting Amethod and the two-step broadcasting B method. Here, a communicationarea length of the wireless LAN is 100 m (50 m in radius), and a movingspeed of the communication terminal 201 a is 5 km/h supposing that thecommunication terminal is carried by a person walking Further, it isassumed that the frequently requested contents data broadcastinginterval 2004 has the same length as the individual contents datatransmission interval 2005 a, and that 80% of requests from thecommunication terminal 201 a are converged to 20% of contents. Stillfurther, as comparative targets to the two-step broadcasting A methodand two-step broadcasting B method, the following cases are considered:a case (1) where the integrated base station 101 a transmits all themetadata and summaries by using communication, a case (2) where theintegrated base station 101 a transmits all the metadata and summariesby using broadcasting, and a case (3) where the metadata is transmittedby using broadcasting and the summaries are transmitted by usingcommunication.

As shown in FIG. 32, in the case where the metadata and the summariesare transmitted by using communication, or in the case where themetadata is transmitted by using broadcasting and the summaries aretransmitted by using communication, the amount of data to be transmittedincreases as the number of users increases, and thus the communicationrate required is increased accordingly. On the other hand, in the casewhere the metadata and the summaries are transmitted by usingbroadcasting, the communication rate required is constant regardless ofthe number of users. Suppose a case where, as a user density, 10 to 40users, each having a technology proposed in the present invention, arepresent in an area of 100 m square. In such a case, the communicationrate required based the two-step broadcasting A method and the two-stepbroadcasting B method is significantly decreased as compared to thatbased on another method.

Embodiment 3

FIG. 33 is a schematic diagram illustrating an overall configuration ofa wireless communication system according to embodiment 3 of the presentinvention. In FIG. 33, the wireless communication system includes anintegrated base station 10 lb, a communication terminal 201 b, and aserver 10. In embodiment 3, as compared to embodiments 1 and 2, in orderto reduce time required before starting communication, other wirelesscommunication (hereinafter referred to as control-wirelesscommunication) than the wireless LAN communication is used, andcommunication channel information and identification information of theintegrated base station 101 b are exchanged in advance. Accordingly, itis possible to reduce time required for searching for a communicationchannel in the integrated base station 101 b, for example, as shown inFIG. 3. In addition, the integrated base station 101 b transmits beaconsat predetermined intervals when the wireless LAN communication is used.Thus, it is possible to reduce waiting time during which thecommunication terminal 20 lb waits for transmission of the beacons fromthe integrated base station 101 b.

The control-wireless communication may be adapted to all communicationmethods in which the integrated base station 10 lb and the communicationterminal 20 lb operate independently of each other, and which allowsspot communication. Since operation in energy saving mode is preferable,the communication method such as a Zigbee may be considered as aprospect of the control-wireless communication. By using thecontrol-wireless communication requiring low power consumption, it ispossible to reduce battery consumption in the communication terminal 20lb. In addition, in the control-wireless communication, thecommunication terminal 201 b preferably has a function of automaticallywaking up from a sleeping state to start communication (WOR: Wake OnRadio) when entering a communication area. Accordingly, thecommunication terminal 20 lb waits while using a saved power in an areaoutside a communication area, and wakes up from the sleeping state whenbeing moved into the communication area, so as to be automaticallyconnected to the integrated base station 101 b. Therefore, by using thecontrol-wireless communication, the communication terminal 20 lbcontinuously searches for an area while using the saved power, and isable to be connected to the integrated base station 101 b promptly upondetection of the area.

The Bluetooth may be one of the prospects for low power consumptiontechnology, however, this method does not have the WOR function, andthus it is unfit to utilize Bluetooth to perform the above-describedoperation. In addition, it is desirable that a process time before startof communication is short. In this regard, Zigbee is more preferablethan Bluetooth since Bluetooth requires about several seconds forconnection. As another prospect, a DSRC (Dedicated Short RangeCommunication) system, which is a communication method developed forhigh-speed vehicles, is able to achieve high-speed connection, and thusis preferable. The DSRC is a wireless method capable of transmittinginformation to a communication terminal at a high speed. Thus, use ofthis method enables the communication terminal 20 lb to reduce time fortransmitting/receiving contents from an integrated base station 101 b,and thus this method is also preferable in this regard.

As a physical layer used for the control-wireless communication, variousspecified low power wireless communication such as a UHF band and thelike, and a UWB (Ultra Wide Band) and the like may be used, in additionto the physical layer used for the above-described communicationmethods. Further, without limiting to the wireless communication,optical communication using an optical beacon, for example, may be used.

FIG. 34 is a block diagram showing an exemplary configuration of theintegrated base station 101 b according to embodiment 3 of the presentinvention. In FIG. 34, the integrated base station 101 b furtherincludes a control-wireless communication section 110 in contrast to theintegrated base stations 101 and 101 a according to embodiments 1 and 2.A control section 104 further includes a control wireless controlsection 109. Respective sections in the integrated base station 101 bare connected via a system bus, and thus are able to transfer datamutually. An external information communication section 102 is designedto transfer contents information from the server 10 to a memory 103 bymeans of a wired communication technology such as Ethernet (registeredtrademark), or to transfer information in the memory 103 to the server10, conversely.

A base station control section 120 has an access restriction section 121and a contents memory section 122. The access restriction section 121monitors a connection type of the communication terminal 201 b which isconnected to the integrated base station 101 b, and permits access fromthe communication terminal 201 b to the server 10 and to the contentsmemory section 122 when the connection type is the second connection. Onthe other hand, the access restriction section 121 prohibits the accessfrom the communication terminal 201 b to the server 10 when theconnection type is the first connection, and permits access to thecontents memory section 122 only. The contents memory section 122 mainlycaches highly public contents among information in the server 10. Thehighly public contents are, for example, typified by town touristinformation, store information, news information, weather information,traffic information, and the like.

The control section 104 includes a communication control section 123, acontrol-wireless control section 109, and a wireless LAN control section108. The communication control section 123 is a section for controllingthe whole of the integrated base station 101, and includes a profileinformation control section 115, a communication control informationstorage section 126, a receiving buffer section 215, and a transmittingbuffer section 219. The profile information control section 115 isdesigned to store information (i.e., profile information or the like)necessary for the communication terminal 201 b to establish connectionwith the wireless LAN communication section 105 through communication.The profile information has been described above.

The communication control information storage section 126 stores thereinan instruction set for controlling the control wireless control section109 and the wireless LAN control section 108. The receiving buffersection 215 is used for buffering information received by the wirelessLAN control section 108 and the control wireless control section 109. Ina similar manner, the transmitting buffer section 219 is used forbuffering information to be transmitted by using the wireless LANcontrol section 108 and the control wireless control section 109.

The control wireless control section 109 is a section for controllingthe control-wireless communication, and includes a frame generation andtransmission/reception control section 124 for controlling generation ofa frame and transmission/reception of a frame. In a similar manner, thewireless LAN control section 108 is a section for controlling thewireless LAN communication, and includes a frame generation andtransmission/reception control section 125. The wireless LANcommunication section 105 includes a transmitting section 106, areceiving section 107, and an antenna section 113. Further, thecontrol-wireless communication section 110 includes a transmittingsection 111, a receiving section 112, and an antenna section 114. Thewireless LAN startup information storage section 501 retains informationfor starting the wireless LAN communication section 804 of thecommunication terminal 201 b, and transmits startup information to thecontrol wireless control section 109, whereby the wireless LAN startupinformation is attached to a packet transmitted by using thecontrol-wireless communication.

FIG. 35 is a block diagram showing an exemplary configuration of thecommunication terminal 201 b according to embodiment 3 of the presentinvention. As shown in FIG. 35, respective sections in the communicationterminal 201 b are connected via a system bus, and thus are able totransfer data mutually. A wireless LAN communication section 804includes a transmitting section 207, a receiving section 208, an antennasection 209, and a wireless LAN power supply section 807. Thecontrol-wireless communication section 210 includes a transmittingsection 211, a receiving section 212, and an antenna section 213.

The control section 802 includes a control-wireless control section 203,a communication control section 226, and a wireless LAN control section805. The communication control section 226 controls the wireless LANcontrol section 805 and the control-wireless control section 203. Thecontrol-wireless control section 203 includes a frame generation andtransmission/reception control section 224 for controlling generationand transmission/reception of a frame. The wireless LAN control section805 includes a wireless LAN power supply control section 806, a profileinformation setting section 205, and a frame generation andtransmission/reception control section 225. The profile informationsetting section 205 obtains, from a profile information storage section214, profile information of the wireless LAN to be connected thereto,and sets connection information for its own wireless LAN communication.

The memory 220 is used for storing and buffering data of communicationterminal 201 b. The memory 220 includes a profile information storagesection 214, a communication control information storage section 223, areceiving buffer section 215, and a transmitting buffer section 219. Theprofile information storage section 214 stores therein information(i.e., profile information or the like) which is received by thecommunication terminal 201 b and is necessary for establishingconnection with the integrated base station 10 lb. Further, thecommunication control information storage section 223 stores therein aninstruction set necessary for the communication terminal 201 b toperform communication.

The terminal control section 227 is a section for controlling terminalfunctions of the communication terminal 20 lb, and includes a requestcontents filter section 221, a display control section 216, and a userattribute extraction section 222. The display control section 216controls information to be displayed on a display section 218 of thecommunication terminal 20 lb. The user attribute extraction section 222extracts an attribute and a preference of a user, based on informationfrom a sensor section 228. Based on a user attribute extracted by theuser attribute extraction section 222, the request contents filtersection 221 filters the metadata received from the integrated basestation 101 b to obtain contents which are considered to be highlypreferred by the user of the communication terminal 20 lb. The requestinformation obtained through filtering by the request contents filtersection 221 is transmitted from the communication terminal 201 b to theintegrated base station 101 b. Accordingly, the communication terminal201 b is able to receive contents that strongly correlate with thepreference of the user of the terminal.

Description of the process thereafter is the same as that described inembodiment 1 or 2, and thus will be omitted.

In embodiment 3 of the present invention, the method has been describedin which the integrated base station 10 lb transmits communicationchannel information and identification information to the communicationterminal 201 b by using control-wireless communication, so as toestablish a high-speed connection with the integrated base station 101b. However, the control-wireless communication may not only transmitinformation for connecting to the integrated base station 101 b rapidly.The integrated base station 101 b may also transmit, for example, themetadata information by using the control-wireless communication.Accordingly, the communication terminal 201 b is able to obtain contentsinformation retained by the integrated base station 101 b withoutstarting the wireless LAN. Thus, when there is no information desired bythe communication terminal 201 b, the communication terminal 201 b isable to operate without starting the wireless LAN, and consequently itis possible to reduce power consumption of the communication terminal201 b.

Further, the integrated base station 101 b may transmit contents byusing the control-wireless communication. That is, the integrated basestation 101 b retains, in the contents memory section 122, highlyimportant information, among contents to be transmitted by using thewireless LAN, or simplified information which is obtained by reducing anamount of data of contents to be transmitted by using the wireless LAN,and transmits the information via the control-wireless communication.Accordingly, the following manner of usage may be proposed: a lowfunction terminal including the control-wireless communication only, forexample, obtains town information in an audio form, whereas a highfunction terminal including a wireless LAN function obtains detailedtown information having guide maps, recommended spot information, andthe like attached thereto by using the wireless LAN.

Embodiment 4

Embodiment 4 has a configuration based on embodiments 1 to 3 in which anantenna section 113 of an integrated base station 101 is replaced with aplurality of antennas. FIG. 36A is a diagram showing an exemplaryoverall configuration in which the antenna section 113 used inembodiment 1 or 2 of present invention is replaced with a plurality ofantennas. In FIG. 36A, a wireless communication system includes a server10, the integrated base station 101, and a communication terminal 201.The integrated base station 101 includes a plurality of antenna sections113. Here, a case will be illustrated where the antenna section 113 ofthe integrated base station 101 consists of antennas 1131 and 1132.

For transmission, the integrated base station 101 may use the pluralityof antennas 1131 and 1132 to transmit a common piece of information fromeach of the antennas 1131 and 1132 in time-division. Alternatively,divided by cables or using a plurality of transmitting sections, acommon piece of information may be transmitted simultaneously. Forsimultaneous transmission, a modulation scheme needs to be applied so asto avoid interference and deterioration of signals from differentantennas. For example, preferably used are: a spread spectrum scheme; anorthogonal frequency division multiplexing (OFDM) modulation scheme; andan anti-multipath modulation scheme which includes redundancy ininformation symbols. Examples of the anti-multipath modulation schemeare: a PSK-VP scheme (Phase Shift Keying with Varied Phase) which has aredundant phase waveform introduced into information symbols of adifferential phase shift keying; an MC-PSK scheme (Manchester CodedPhase Shift Keying); an SPSK scheme (Stepped Phase Shift Keying); andthe like. Further, different redundant phase waveforms may be used forthe antennas 1131 and 1132, individually.

Other examples of the anti-multipath modulation scheme are: a PSK-RZscheme (Phase Shift Keying with Return-to-Zero) which has a redundantamplitude waveform introduced into information symbols of a differentialphase shift keying; a DSK scheme (Double Shift Keying) performing aphase-shift twice depending on transmitting information; and the like.In addition, in order to avoid mutual interference and deterioration,there may be used: an FSK (Frequency Shift Keying) modulation scheme inwhich redundant signals are mutually superimposed, or differentmodulation parameters are arranged for respective antennas; an ASK(Amplitude Shift Keying) modulation scheme having a short duty cycle inwhich signals to be transmitted are displaced from and not superimposedmutually.

For receiving signals, the integrated base station 101 may combinesignals received via the plurality of antennas 1131 and 1132, or selectone having a good quality (signal intensity or the like). Alternatively,the integrated base station 101 may includes a plurality of receivingsections so as to combine signals by appropriately adjusting theirphases, or to combine signals into a reception data sequence byselecting and joining a plurality of received data in data blockswithout errors. The synthesis of the reception data sequence may berealized by encoding the signal on the transmission side in advance soas to detect errors.

FIG. 36B is a diagram showing an exemplary wireless LAN communicationsection transmitting/receiving a signal using the plurality of antennas1131 and 1132 shown in FIG. 36A. In FIG. 36B, a signal transmitted fromthe transmitting section 106 is divided by cables, provided to theantennas 1131 and 1132, and then radiated, respectively. The signalsreceived by the antennas 1131 and 1132 are combined together andinputted to a receiving section 107, and then detected and decoded.Appropriate delay which is decided depending on a modulation schemeneeds to be added to the signals, but the delay insertion may beachieved by a difference between the lengths of the cables.

FIG. 36C is a diagram showing an exemplary wireless LAN communicationsection which transmits/receives a signal using the plurality ofantennas 1131 and 1132 shown in FIG. 36A. As shown in FIG. 36C, thereare transmitting sections 1061 and 1062, and receiving sections 1071 and1072 corresponding to the antennas 1131 and 1132, respectively. Fortransmission, a common piece of information or a transmitting signal isdivided by a transmission dividing section 1001 and distributed to thetransmitting sections 1061 and 1062 at appropriate timings, and areradiated via the antennas 1131 and 1132. Distribution may be made in anyform such as transmission data, a transmission baseband signal, ahigh-frequency signal including a modulated intermediate frequency, andthe like. For reception, signals received from the antennas 1131 and1132 are detected or decoded at the receiving sections 1071 and 1072,respectively, and are combined by a reception combining section 1002 toobtain received data. For synthesis, the detected signals may be addedtogether. Alternatively, the signals are encoded on the transmissionside in advance such that errors therein can be detected, and, at thereception combining section 1002, pluralities of decoded data sequencesare joined together into a received data sequence by selecting in datablocks without errors. Accordingly, the plurality of decoded datasequences are combined, and a received data sequence may be obtained.

FIG. 36D is a schematic diagram illustrating an exemplary case of an ASKmodulation scheme having a short duty cycle, in which signalstransmitted simultaneously are combined on a reception side. In thisexample, in the case of transmitting information “1”, two kinds oftransmission signal A for transmitting a high-frequency signal duringonly former half of a symbol and transmission signal B for transmittingthe same during only latter half of the symbol, respectively, aretransmitted via individual antennas simultaneously. In the case oftransmitting the information “1” under a normal ASK modulation scheme,the high-frequency signal is transmitted during a whole one symbol,however, in this case, signals from the plurality of antennas 1131 and1132 will be opposite to each other in phase, in some overlapped area,due to phase rotation caused by propagation delay time difference, andconsequently the signals are cancelled by each other, and an area wheresignals cannot be received will occur. On the other hand, as in the caseof the present invention, when a high-frequency signal is transmittedduring only the former half of a symbol and during only the latter halfof a symbol, such cancellation will not occur. That is, on the receptionside, each half of the received waveforms, when each having a shorterpropagation time than the symbol duration, are sequenced in acorresponding symbol. Thus, respective signals do not interfere witheach other, and the information “1” and “0” can be decoded by detectingall the received power in the symbol. This example is not onlyapplicable to wireless communication, but is also applicable to opticalcommunication such as infrared light and the like, and an on-off keying(OOK) is applicable to the optical communication as it is. Theabove-described communication method is not only applicable to thewireless communication system, but is also applicable to a system oftransmitting a signal using a plurality of antennas.

In the example shown in FIG. 36A, wireless areas covered by theplurality of antennas 1131 and 1132 are generally overlapped with eachother. Accordingly, unstable communication, which is caused by fadingdue to multipath propagation derived from reflection and diffraction bysurrounding objects, and caused by shadowing due to obstructions on aline of sight or a user carrying the communication terminal 201, areimproved, and area boundaries are stabilized. Thus, a user can startcommunication promptly upon entrance to a communication area. To avoidthe shadowing, the antennas 1131 and 1132 are preferably spaced at awider distance.

FIG. 37 is a diagram showing an exemplary overall configurationaccording to embodiment 1 or 2 of present invention in which the antennasection 114 is replaced with a plurality of antennas. In FIG. 37, thewireless communication system includes an integrated base station 101 band a communication terminal 201 b, and the integrated base station 101b includes a plurality of antenna sections 114. Here described is anexample where two antennas 1141 and 1142 are used for thecontrol-wireless communication, and an antenna 113 is used for thewireless LAN communication.

As compared to the example shown in FIG. 36A, the wireless communicationsystem shown in FIG. 37 uses a plurality of antennas, and the pluralityof antennas are used as control-wireless antennas 1141 and 1142, not asthose for the wireless LAN communication. However, the plurality ofantennas are used in the same manner as those in example shown FIG. 36A,and thus detailed description will be omitted. In the example shown inFIG. 37, wireless areas covered by the plurality of antennas 1141 and1142 for the control-wireless communication are arranged so as to beoverlapped with each other, in general. In addition, a wireless areacovered by the antenna 113 for the wireless LAN communication is alsoarranged so as to be overlapped with the above wireless areas. Theplurality of antennas 1141 and 1142 for the control-wirelesscommunication reduces an effect of fading caused by multipathpropagation and shadowing caused by obstructions, and thus areaboundaries are stabilized. Accordingly, when the communication terminal201 b enters a wireless area, it is possible to start communicationpromptly, and also possible to allow the communication to be promptlyswitched to the wireless LAN communication. In this manner, it ispossible for the integrated base station 10 lb and the communicationterminal 20 lb to detect entrance of the communication terminal 20 lbinto the wireless area of the integrated base station 10 lb whilemaintaining power saving, and to start communication promptly.

FIG. 38 is a diagram showing an exemplary overall configurationaccording to one of embodiments 1 to 3 of the present invention in whichthe antenna section is replaced with a plurality of antennas. In FIG.38, a wireless communication system includes the integrated base station101 and the communication terminal 201, and the integrated base station101 includes a plurality of antenna sections. Here, described is anexemplary case where, as the antenna sections, four antennas 1131, 1132,1133, and 1134 are provided to the integrated base station 101. Theantenna sections may be for the wireless LAN communication, or may befor the control-wireless communication. In the case where the antennasections are for the control-wireless communication, one or moreantennas for the wireless LAN communication are needed additionally forcovering one or more wireless areas which include the wireless areascovered by the plurality of antennas for the control-wirelesscommunication. However, the one or more antennas are omitted here.

The plurality of antennas is used in the same manner as described above,and thus description thereof will be omitted. In the example shown inFIG. 38, the wireless areas covered by the plurality of antennas 1131,1132, 1133, and 1134 are arranged linearly or planarly in a manner to bepartially overlapped with one another. Accordingly, the wireless areasare configured artificially, and communication can be started promptlyin such connected areas. When a plurality of antennas are used for thecontrol-wireless communication, the wireless LAN communication areas arearranged so as to be included in the connected areas for thecontrol-wireless communication, whereby communication using thecontrol-wireless communication is started before the communicationterminal 201 enters the wireless LAN area, and the communication can bepromptly switched to the wireless LAN communication.

FIG. 39A is a diagram showing an exemplary overall configurationaccording to one of embodiments 1 to 3 of the present invention in whichthe antenna section is replaced with a plurality of antennas. In FIG.39A, a wireless communication system includes the integrated basestation 101 and a communication terminal 2011 or 2012, and theintegrated base station 101 includes a plurality of antenna sections.Here, described is an exemplary case where, as the antenna sections, thefour antennas 1131, 1132, 1133, and 1134 are provided to the integratedbase station 101. In this case as well, the antenna sections may be usedfor the wireless LAN communication, or may be used for thecontrol-wireless communication.

In the case where the antenna sections are for the control-wirelesscommunication, one or more antennas for the wireless LAN communicationare needed for covering one or more wireless areas which include thewireless areas covered by the plurality of antennas for thecontrol-wireless communication. However, the one or more antennas areomitted here. The integrated base station 101 has a contents memory 11including therein metadata 1906, frequently requested contents data1907, and individually requested contents data 1908.

FIG. 39B is a diagram showing an exemplary configuration of acommunication section transmitting/receiving a signal using theplurality of antennas shown in FIG. 39A. As shown in FIG. 39B, thecommunication section includes transmitting sections 1061, 1062, 1063,and 1064, and receiving sections 1071, 1072, 1073, and 1074, whichcorrespond to antennas 1131, 1132, 1133, and 1134, respectively.Depending on the type of data to be transmitted/received, informationcan be transmitted/received to/from the four antennas simultaneously viaa transmission dividing section 1001 and a reception combining section1002. Alternatively, different pieces of information can betransmitted/received to/from the antennas, individually.

The plurality of antennas is used in the same manner as described above,and thus description thereof will be omitted. In the example shown inFIG. 39A, the wireless areas covered by the plurality of antennas 1131,1132, 1133, and 1134 are arranged linearly or planarly in a manner to beat least partially overlapped with one another. Starting ofcommunication, broadcasting of the metadata 1096, and broadcasting ofthe frequently requested contents data 1907 are performed in the samemanner as those shown in FIG. 38, and thus description thereof will beomitted. The individually requested contents data 1908 is transmitted ina different manner. That is, a request for the data is made from anantenna (the antenna 1134 or 1131, in this case) of the communicationterminal 2011 or 2012, and corresponding individually requested contentsdata is returned from the same individual antenna.

In this manner, the metadata 1906 and the frequently requested contentsdata 1907 which are common to all terminals are transmitted (orreceived) via all the antennas 1131, 1132, 1133, and 1134, whereas theindividually requested contents data 1908 which is requested byindividual communication terminals is transmitted/received viaindividual antennas independently of one another. As a result, it ispossible to achieve superior response and throughput as a whole.

Further, process procedures performed by the respective function blocksdescribed in the respective embodiments of the present invention may berealized by a CPU interpreting and executing predetermined program datacapable of executing the above-described process procedures stored on astorage device (a ROM, a RAM, a hard disc, and the like). In this case,the program data may be introduced into the storage device via a storagemedium, or may be directly executed on the storage medium. Here, thestorage medium includes: a semiconductor memory such as a ROM, a RAM, aflash memory and the like; a magnetic disc memory such as a flexibledisc, hard disc, and the like; an optical disc memory such as a CD-ROM,a DVD, a BD, and the like; and a memory card and the like. Further, thestorage medium is a notion including a communication medium such as aphone line, a carrier path, and the like.

Further, each of the respective function blocks described in therespective embodiments of the present invention is typically executed asan LSI, an integrated circuit. The function blocks may be each providedin a chip form, or some or all of the function blocks may be provided ina chip form. The LSI may be referred to as an IC, a system LSI, a superLSI, an ultra LSI depending on the degree of integration.

Further, the method of integration is not limited to the LSI, and may berealized by a dedicated circuit or a general purpose processor.Alternatively, an FPGA (Field Programmable Gate Array) which isprogrammable after manufacturing the LSI, or a reconfigurable processorenabling reconfiguration of connection or setting of a circuit cell inthe LSI may be used. Still alternatively, a configuration may be used inwhich, a hardware resource includes a processor, a memory, and the like,and the processor executes and controls a control program stored in aROM.

Still further, in the case where another integration technologyreplacing the LSI becomes available due to an improvement of asemiconductor technology or due to emergence of another technologyderived therefrom, the function blocks may be integrated using such anew technology. For example, biotechnology may be applied.

The present invention is useful, for example, as a technology whichallows a user to receive a large amount of communication contents and todisplay contents desired by the user when his/her communication terminalpasses through a communication area of an access point.

While the invention has been described in detail, the foregoingdescription is in all aspects illustrative and not restrictive. It isunderstood that numerous other modifications and variations can bedevised without departing from the scope of the invention.

1. A wireless base station connected to a plurality of wirelesscommunication terminals and receiving contents via a network, thewireless base station comprising: a network communication controlsection that controls communication with the network; a wirelesscommunication section that communicates with the plurality of wirelesscommunication terminals in accordance with a predetermined communicationmethod; and a control section that controls the wireless communicationsection, wherein an interval connected between the wirelesscommunication section and the plurality of wireless communicationterminals includes a contents data broadcasting interval and a contentsdata transmitting interval, the control section collectively broadcaststhe first contents data to the plurality of wireless communicationterminals in the contents data broadcasting interval, and transmits thesecond contents data to at least one of the wireless communicationterminals in the contents data transmitting interval by controlling thewireless communication section, the first contents data and the secondcontents data respectively are a part of the contents received via thenetwork, and the second contents data is selected based on requestinformation which is received from the plurality of wirelesscommunication terminals.
 2. The wireless base station according to claim1, further comprising: a contents memory section that stores the firstcontents data and the second contents data received via the network. 3.The wireless base station according to claim 1, wherein the controlsection collectively broadcasts, in advance of the contents datatransmitting interval, the first contents data to the plurality ofwireless communication terminals and transmits the second contents datato at least one of the wireless communication terminals in the contentsdata transmitting interval by controlling the wireless communicationsection.
 4. The wireless base station according to claim 2, wherein thecontents memory section further stores therein a metadata relating tothe first contents data and to the second contents dada, and the controlsection, in advance of the first contents data is broadcasted, transmitsthe metadata to the plurality of wireless communication terminals, andreceives a contents request packet containing information indicatingcontents that the plurality of wireless communication terminal requireby controlling the wireless communication section.
 5. The wireless basestation according to claim 2, wherein the contents memory sectioninterchanges the first contents data and the second contents data witheach other in accordance with the request information from the pluralityof wireless communication terminals.
 6. The wireless base stationaccording to claim 1, wherein the first contents data, of whichtransmitting frequency from the plurality of wireless communicationterminals is higher than the second contents data, is broadcasted to theplurality of wireless communication terminals.
 7. The wireless basestation according to claim 1, wherein the wireless communication sectionconnects to the plurality of wireless communication terminals with awireless LAN communication method.
 8. The wireless base stationaccording to claim 1, further comprising: a control-wirelesscommunication section that performs communication in accordance with acontrol-communication method, wherein the control section, in advance ofthe communication between the wireless communication section and theplurality of wireless communication terminals, obtains settinginformation that is necessary for the wireless communication section andthe plurality of wireless communication terminals to communicate inaccordance with the predetermined communication method by controllingthe control-wireless communication section.
 9. A wireless communicationterminal, included in a plurality of wireless communication terminals,connected to a wireless base station which receives contents via anetwork, the wireless communication terminal comprising: a wirelesscommunication section that communicates with the wireless base stationin accordance with a predetermined communication method; a controlsection that controls the wireless communication section; and a terminalcontrol section that controls transmission of information on a contentsrequest to the wireless base station, wherein an interval connectedbetween the wireless communication section and the wireless base stationincludes a contents data broadcasting interval and a contents dadatransmitting interval, the wireless communication section receives thefirst contents data, which the wireless base station collectivelybroadcasted to the plurality of wireless communication terminals in thecontents data broadcasting interval, and the second contents data, whichthe wireless base station transmitted to at least one of the wirelesscommunication terminals in the contents data transmitting interval, thefirst contents data and the second contents data respectively are a partof the contents received via the network by the wireless base station,and the second contents data is transmitted, by the wireless basestation, based on request information which the wireless base stationreceived from the plurality of wireless communication terminals.
 10. Thewireless communication terminal according to claim 9, wherein thewireless communication section receives metadata relating to thecontents from the wireless base station, and the terminal controlsection transmits a contents data request packet to the wireless basestation to request for a contents data which the wireless communicationterminal desires to receive among the received metadata.
 11. Thewireless communication terminal according to claim 9, furthercomprising: a control-wireless communication section that performscommunication in accordance with a control-communication method, whereinthe control section, in advance of the communication between thewireless base station and the wireless communication section, obtainssetting information that is necessary for the wireless base station andthe wireless communication section to communicate in accordance with thepredetermined communication method by controlling the control-wirelesscommunication section.
 12. A wireless communication system in which awireless base station, which receives contents via a network, and aplurality of wireless communication terminals are connected to eachother, the wireless base station comprising; a network communicationcontrol section that controls communication with the network; a basestation side wireless communication section that communicates with theplurality of wireless communication terminals in accordance with apredetermined communication method; and a base station side controlsection that controls the base station side wireless communicationsection, wherein an interval connected between the base station sidewireless communication section and the plurality of wirelesscommunication terminals includes a contents data broadcasting intervaland a contents data transmitting interval, the base station side controlsection collectively broadcasts the first contents data to the pluralityof wireless communication terminals in the contents data broadcastinginterval, and transmits the second contents data to at least one of thewireless communication terminals in the contents data transmittinginterval by controlling the base station side wireless communicationsection, the first contents data and the second contents datarespectively are a part of the contents received via the network, thesecond contents data is selected based on request information which isreceived from the plurality of wireless communication terminals, each ofthe wireless communication terminals comprises: a terminal side wirelesscommunication section that communicates with the wireless base stationin accordance with the predetermined communication method; and aterminal side control section that controls the wireless sidecommunication section, the terminal side control section that controlstransmission of information on a contents request to the wireless basestation, and the terminal side wireless communication section receivesthe first contents data, which the wireless base station collectivelybroadcasted to the plurality of wireless communication terminals in thecontents data broadcasting interval, and the second contents data, whichthe wireless base station transmitted to at least one of the wirelesscommunication terminals in the contents data transmitting interval. 13.The wireless base station according to claim 1, wherein the controlsection broadcasts the second contents data to the plurality of wirelesscommunication terminals in the contents data transmitting interval bycontrolling the wireless communication section.